The Time-Course Closing Process of the Arytenoids and Laryngeal Vestibule with Fiberoptic Endoscopic Examination of Swallowing (FEES)
In order to analyze the laryngeal movement during swallowing, we stimulated electrically the sensory branch of the superior laryngeal nerve (SLN) in rats and evaluated the time-course of movemment of the arytenoids and laryngeal vestibule with fiberoptic endoscopic examination of swallowing (FEES). The initiation time of laryngeal closure (ITLC) and the lasting time of laryngeal closure (LTLC) were compared between 24 normal rats and 20 unilateral SLN paralyzed rats. ITLC was the time between stimulation of the right sensory branch of the SLN and the beginning of the adductive movement of the arytenoids and laryngeal vestibule. LTLC was the time between the beginning of the adductive movement of the arytenoids and return of them. In this experiment, patterns of the adductive movement of the arytenoids and laryngeal vestibule occurred similarly in the unilateral SLN paralyzed group to the normal group. However, ITLC was delayed in rats with unilateral SLN paralysis compared to that in normal rats. There were no significant differences in LTLC between the paralyzed group and normal group. The present study suggests that ITLC is an important value for evaluating the function of protecting the lower respiratory tract during swallowing.